Originally, when John Masterson devised the format in 1975, he originally pitched it to Stefan Hatos-Monty Hall Productions (responsible for various shows including Lets Make A Deal and Split/Second). Hatos and Hall were interested and gave Masterson a one-year option to sell the show. Unfortunately, the networks weren't interested and the option ran out.
Joseph Wapner almost didn't get the judge's seat. When Ralph Edwards and Stu Billett pitched the show to NBC, the network wanted a black comedian like Nipsey Russell or Pigmeat Markham to preside, all the while making jokes during the proceedings (although after a commercial break, he'd be coached by a real judge and would then give his decision). NBC had Edwards and Billett shoot two pilots, one with Wapner and one with Markham, after which the network would determine which would go to air. After taping the Wapner pilot, Edwards and Billett felt they just couldn't do a Markham pilot because it'd be too campy, and instead decided to bypass the networks and go straight to First Run Syndication.
Similarly, Rusty Burrell was almost passed over for the bailiff's position because Stu Billett originally wanted a "sexy girl" to be the bailiff. It was only at Wapner's insistence that Rusty got the job.